Note: Descriptions are shown in the official language in which they were submitted.
Apparatuses and Methods for Dispensing Flowable Materials
TECHNICAL FIELD
The present disclosure generally relates to apparatuses and methods for
dispensing flowable materials and, more specifically, to dispensing flowable
materials
using rotary actuators and hydraulic means.
BACKGROUND
Flowable materials are commonly dispensed using direct mechanical action.
For example, a manual caulking gun has a trigger, configured to advance a
plunger
that extrudes material from a cartridge. However, manual activation of the
trigger to
extrude the flowable material, which often has a glutinous consistency, is
physically
demanding and, accordingly, difficult to control. Pneumatic action is readily
available
to supplement or replace direct mechanical action when force amplification is
required. However, compressible nature of gases results in a loss of precision
when
pneumatic action is used for dispensing flowable materials. Overall,
conventional
devices and methods of dispensing flowable materials lack precision, needed in
certain critical applications, such as aerospace.
SUMMARY
Accordingly, apparatuses and methods, intended to address at least the
above-identified concerns, would find utility.
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The following is a non-exhaustive list of examples, which may or may not be
claimed, of the subject matter disclosed herein.
One example of the subject matter, disclosed herein, relates to an apparatus
for dispensing a flowable material. The apparatus comprises a rotary actuator,
a
reservoir, containing a hydraulic fluid, a piston, movable inside the
reservoir, a linear
actuator, coupled to the piston, a gear train, coupling the rotary actuator
with the
linear actuator, and a flowable-material dispenser, hydraulically coupled with
the
reservoir.
Using the rotary actuator and direct mechanical or hydraulic coupling between
various components of the apparatus provides high dispensing precision.
Specifically, the linear movement of the piston inside the reservoir,
containing the
hydraulic fluid, is precisely controlled by the rotary actuator, such as a
stepper motor.
The rotary actuator is coupled to the linear actuator using the gear train,
while the
linear actuator is coupled to the piston. The linear movement of the piston
transfers at
least a portion of the hydraulic fluid between the reservoir and the flowable-
material
dispenser. The hydraulic fluid, once transferred to the flowable-material
dispenser,
displaces the flowable material from the flowable-material dispenser in a
precise
manner. It should be noted that the volume of the hydraulic fluid, displaced
from the
reservoir, is the same as the volume of the hydraulic fluid received in the
flowable-
material dispenser since hydraulic fluid is not compressible. As such, the
dispensing
of the flowable material is precisely controlled by the movement of the piston
inside
the reservoir, which in turn is precisely controlled by the rotary actuator.
Overall, the
rotary actuator controls precise dispensing of the flowable material through
mechanical and hydraulic coupling between various components of the apparatus.
Furthermore, the hydraulic coupling allows more flexible positioning of the
flowable-
material dispenser relative to the rotary actuator, thereby resulting in the
apparatus
being compact.
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Another example of the subject matter, disclosed herein, relates to a method
for dispensing a flowable material using an apparatus. The apparatus comprises
a
rotary actuator, a reservoir, containing a hydraulic fluid, a piston, movable
inside the
reservoir, a linear actuator, coupled to the piston, a gear train, coupling
the rotary
actuator with the linear actuator, a flowable-material dispenser, comprising a
cartridge
housing and a plunger and hydraulically coupled with the reservoir, an end-
cap,
movably coupled with the flowable-material dispenser, and an over-center
mechanism, movably coupling the end-cap with the cartridge housing of the
flowable-
material dispenser. The method comprises holding the hydraulic fluid in the
reservoir
at a negative pressure, sufficient to generate a vacuum between the end-cap
and the
plunger, inserting a cartridge tube, having an interior, into the cartridge
housing,
wherein the flowable material is inside the cartridge tube, locking the over-
center
mechanism relative to the cartridge housing so that a hermetic seal is created
between the plunger and the interior of the cartridge tube and between the end-
cap
and the interior of the cartridge tube, and turning the rotary actuator in a
rotational
direction so that the linear actuator advances the piston within the reservoir
to transfer
at least a portion of the hydraulic fluid from the reservoir to the flowable-
material
dispenser through the end-cap and into the interior of the cartridge tube,
causing the
plunger to advance within the cartridge tube in a forward plunger direction,
away from
the end-cap.
When the hydraulic fluid is held at the negative pressure in the reservoir,
this
negative pressure is also present in all other areas of the apparatus occupied
by the
hydraulic fluid. As a result, the plunger, which contacts the hydraulic fluid,
is forced
by the hydraulic fluid toward and against the end-cap. This force supports the
plunger on the end-cap and allows positioning the plunger away from the
cartridge
housing when the end-cap is moved away from the cartridge housing. This
position of
the plunger and the end-cap, away from the cartridge housing, provides access
to the
cartridge housing, allowing insertion of the cartridge tube into the cartridge
housing.
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When the over-center mechanism is locked relative to the cartridge housing,
the plunger is pressed by the end-cap into the interior of the cartridge tube
and is
hermetically sealed against the interior of the cartridge tube. The hermetic
seal
prevents the flowable material from flowing past the plunger. Furthermore, the
hermetic seal prevents the hydraulic fluid from flowing past the plunger and
reaching
the flowable material while still allowing the plunger to advance within the
cartridge
tube.
Another hermetic seal is formed between the end-cap and the interior of the
cartridge tube. This seal keeps the hydraulic fluid within the interior of the
cartridge
tube when the hydraulic fluid is transferred into the interior of the
cartridge tube and
maintained at a positive pressure or a negative pressure (e.g., to advance the
plunger
within the cartridge tube). This seal is maintained while the end-cap is
positioned at a
first end of the cartridge housing.
When the rotary actuator is turned in a rotational direction, the linear
actuator advances the piston within the reservoir. The rotational speed and
the
degree of rotation (e.g., the number of rotations) of the rotary actuator are
precisely
controlled. This control translates into the precise linear motion of the
piston. As the
piston moves within the reservoir, at least a portion of the hydraulic fluid
is transferred
from the reservoir to the flowable-material dispenser. Specifically, the
hydraulic fluid
flows through the end-cap into the interior of the cartridge tube. This
addition of the
hydraulic fluid causes the plunger to advance within the cartridge tube in a
forward
plunger direction away from the end-cap. As a result, the flowable material is
displaced by the plunger out of the cartridge tube. The precision of the
rotary
actuator results in the flowable material being dispensed in a controlled
manner.
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BRIEF DESCRIPTION OF THE DRAWINGS
Having thus described one or more examples of the present disclosure in
general terms, reference will now be made to the accompanying drawings, which
are
not necessarily drawn to scale, and wherein like reference characters
designate the
same or similar parts throughout the several views, and wherein:
FIGS. 1A and 1B, collectively, are a block diagram of an apparatus for
dispensing flowable materials, according to one or more examples of the
present
disclosure;
FIG. 2 is a schematic perspective view of the apparatus of FIGS 1A and 1B,
according to one or more examples of the present disclosure;
FIGS. 3A and 3B are schematic cross-sectional views of a portion of the
apparatus of FIG. 2, according to one or more examples of the present
disclosure;
FIGS. 3C and 3D are schematic cross-sectional views of an anti-rotation
mechanism of the apparatus of FIGS. 1A and 1B, according to one or more
examples
of the present disclosure;
FIGS. 3E and 3F are schematic cross-sectional views of a piston and a
reservoir of the apparatus of FIGS. 1A and 1B, according to one or more
examples of
the present disclosure;
FIG. 4A is a schematic cross-sectional view of a flowable-material dispenser
of
the apparatus of FIG. 2, illustrating a cartridge tube inserted into the
cartridge
housing, according to one or more examples of the present disclosure;
FIG. 4B is a schematic cross-sectional view of the cartridge tube of FIG. 4A,
according to one or more examples of the present disclosure;
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FIG. 4C is a schematic cross-sectional view of a portion of the flowable-
material dispenser in FIG. 4A, illustrating a plunger positioned against an
end-cap,
according to one or more examples of the present disclosure;
FIG. 4D is a schematic cross-sectional view of the portion of the flowable-
material dispenser also shown in FIG. 4B, illustrating the plunger moving away
from
the end-cap, according to one or more examples of the present disclosure;
FIG. 4E is a schematic cross-sectional view of a portion of the flowable-
material dispenser in FIG. 4A, illustrating a cartridge tube sealed against a
second
end-cap, according to one or more examples of the present disclosure;
FIGS. 5A and 5B are schematic side views of a portion of the apparatus in FIG.
2, illustrating operation of an over-center mechanism, according to one or
more
examples of the present disclosure;
FIGS. 6A and 6B are schematic cross-sectional views of a portion of the
flowable-material dispenser in FIG. 4A, illustrating operation of a dispenser
valve,
according to one or more examples of the present disclosure;
FIGS. 7A and 7B, collectively, are a block diagram of a method of dispensing
flowable material using the apparatus of FIGS. 1A, 1B, and 2, according to one
or
more examples of the present disclosure;
FIG. 8A is a block diagram of aircraft production and service methodology; and
FIG. 8B is a schematic illustration of an aircraft.
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DETAILED DESCRIPTION
In FIGS. 1A and 1B, referred to above, solid lines, if any, connecting various
elements and/or components may represent mechanical, electrical, fluid,
optical,
electromagnetic and other couplings and/or combinations thereof. As used
herein,
"coupled" means associated directly as well as indirectly. For example, a
member A
may be directly associated with a member B, or may be indirectly associated
therewith, e.g., via another member C. It will be understood that not all
relationships
among the various disclosed elements are necessarily represented. Accordingly,
couplings other than those depicted in the block diagrams may also exist.
Dashed
lines, if any, connecting blocks designating the various elements and/or
components
represent couplings similar in function and purpose to those represented by
solid
lines; however, couplings represented by the dashed lines may either be
selectively
provided or may relate to alternative examples of the present disclosure.
Likewise,
elements and/or components, if any, represented with dashed lines, indicate
alternative examples of the present disclosure. One or more elements shown in
solid
and/or dashed lines may be omitted from a particular example without departing
from
the scope of the present disclosure. Environmental elements, if any, are
represented
with dotted lines. Virtual (imaginary) elements may also be shown for clarity.
Those
skilled in the art will appreciate that some of the features illustrated in
FIGS. 1A, 1B,
and 1C may be combined in various ways without the need to include other
features
described in FIG. 1A, 1B, and 1C, other drawing figures, and/or the
accompanying
disclosure, even though such combination or combinations are not explicitly
illustrated
herein. Similarly, additional features not limited to the examples presented,
may be
combined with some or all of the features shown and described herein.
In FIGS. 8A and 8B, referred to above, the blocks may represent operations
and/or portions thereof and lines connecting the various blocks do not imply
any
particular order or dependency of the operations or portions thereof. Blocks
represented by dashed lines indicate alternative operations and/or portions
thereof.
Dashed lines, if any, connecting the various blocks represent alternative
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dependencies of the operations or portions thereof. It will be understood that
not all
dependencies among the various disclosed operations are necessarily
represented.
FIGS. 8A and 8B and the accompanying disclosure describing the operations of
the
method(s) set forth herein should not be interpreted as necessarily
determining a
sequence in which the operations are to be performed. Rather, although one
illustrative order is indicated, it is to be understood that the sequence of
the
operations may be modified when appropriate. Accordingly, certain operations
may
be performed in a different order or simultaneously. Additionally, those
skilled in the
art will appreciate that not all operations described need be performed.
In the following description, numerous specific details are set forth to
provide a
thorough understanding of the disclosed concepts, which may be practiced
without
some or all of these particulars. In other instances, details of known devices
and/or
processes have been omitted to avoid unnecessarily obscuring the disclosure.
While
some concepts will be described in conjunction with specific examples, it will
be
understood that these examples are not intended to be limiting.
Unless otherwise indicated, the terms "first," "second," etc. are used herein
merely as labels, and are not intended to impose ordinal, positional, or
hierarchical
requirements on the items to which these terms refer. Moreover, reference to,
e.g., a
"second" item does not require or preclude the existence of, e.g., a "first"
or lower-
numbered item, and/or, e.g., a "third" or higher-numbered item.
Reference herein to "one example" means that one or more feature, structure,
or characteristic described in connection with the example is included in at
least one
implementation. The phrase "one example" in various places in the
specification may
or may not be referring to the same example.
As used herein, a system, apparatus, structure, article, element, component,
or
hardware "configured to" perform a specified function is indeed capable of
performing
the specified function without any alteration, rather than merely having
potential to
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perform the specified function after further modification. In other words, the
system,
apparatus, structure, article, element, component, or hardware "configured to"
perform a specified function is specifically selected, created, implemented,
utilized,
programmed, and/or designed for the purpose of performing the specified
function.
As used herein, "configured to" denotes existing characteristics of a system,
apparatus, structure, article, element, component, or hardware which enable
the
system, apparatus, structure, article, element, component, or hardware to
perform the
specified function without further modification. For purposes of this
disclosure, a
system, apparatus, structure, article, element, component, or hardware
described as
being "configured to" perform a particular function may additionally or
alternatively be
described as being "adapted to" and/or as being "operative to" perform that
function.
Illustrative, non-exhaustive examples, which may or may not be claimed, of the
subject matter according the present disclosure are provided below.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 2,
3A,
3B, and 4D, apparatus 100 for dispensing flowable material 308 is disclosed.
Apparatus 100 comprises rotary actuator 120, reservoir 140, containing
hydraulic fluid
155, and piston 145, movable inside reservoir 140. Apparatus 100 also
comprises
linear actuator 130, coupled to piston 145, gear train 125, coupling rotary
actuator 120
with linear actuator 130, and flowable-material dispenser 160, hydraulically
coupled
with reservoir 140. The preceding subject matter of this paragraph
characterizes
example 1 of the present disclosure.
Using rotary actuator 120 and direct mechanical or hydraulic coupling between
various components of apparatus 100 provides high dispensing precision.
Specifically, the linear movement of piston 145 inside reservoir 140,
containing
hydraulic fluid 155, is precisely controlled by rotary actuator 120, such as a
stepper
motor. Rotary actuator 120 is coupled to linear actuator 130 using gear train
125,
while linear actuator 130 is coupled to piston 145. The linear movement of
piston 145
transfers at least a portion of hydraulic fluid 155 between reservoir 140 and
flowable-
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material dispenser 160.
Hydraulic fluid 155, transferred to flowable-material
dispenser 160, displaces flowable material 308 from flowable-material
dispenser 160
in a precise manner. It should be noted that the volume of hydraulic fluid
155,
displaced from reservoir 140, is the same as the volume of hydraulic fluid 155
received in flowable-material dispenser 160 since hydraulic fluid 155 is not
compressible. As such, the dispensing of flowable material 308 is precisely
controlled
by the movement of piston 145 inside reservoir 140, which in turn is precisely
controlled by rotary actuator 120. Overall, rotary actuator 120 controls
precise
dispensing of flowable material 308 through mechanical and hydraulic coupling
between various components of apparatus 100. Furthermore, the hydraulic
coupling
allows more flexible positioning of flowable-material dispenser 160 relative
to rotary
actuator 120, thereby resulting in apparatus 100 being compact. FIG. 2
illustrates an
example of flowable-material dispenser 160 and rotary actuator 120 being
positioned
along two parallel axes.
Apparatus 100 is configured to dispense various types of flowable materials
308. Some examples of flowable materials 308 include, but are not limited to,
adhesives, sealants, lubricants, viscous materials, thixotropic materials, and
the like.
In some examples, the viscosity of flowable materials 308 is between about
10,000
cps and 1,000,000 cps or, more specifically, between about 50,000 cps and
250,000
cps. High viscosity and other flow characteristics of flowable materials 308
require
high displacement forces, which interferes with precision of conventional
methods.
On the other hand, hydraulic coupling between different components of
apparatus
100 allows generating high displacement forces without compromising
displacement
precision.
Some examples of rotary actuator 120 include, but are not limited to, stepper
motors, servo motors, and the like. The rotational speed and degree of
rotation (e.g.,
the rotational angle and/or the number of rotations) of rotary actuator 120 is
precisely
controlled. As further described below, various inputs, e.g., pressure inside
reservoir
140, are used for controlling rotary actuator 120. The rotational speed
controls the
CA 3052166 2019-08-14
dispensing rate (e.g., the flow rate) of flowable material 308 from apparatus
100. The
degree of rotation controls the amount of flowable material 308 dispensed from
apparatus 100.
Precision of the dispensing rate and/or the dispensed amount of flowable
.. material 308 is also enhanced by gear train 125 and/or linear actuator 130.
In some
examples, gear train 125 provides a rotation speed reduction from rotary
actuator 120
and linear actuator 130 thereby increasing the precision of linear actuator
130. In
these examples, the gear ratio is between about 1.5 and 30 and, more
specifically,
between about 2 and 10. The gear ratio is defined as a ratio of the number of
teeth
on an input gear, coupled to rotary actuator 120, to the number of teeth on an
output
gear, coupled to linear actuator 130.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4A-
4E,
flowable-material dispenser 160 comprises cartridge housing 173 and plunger
175.
Cartridge housing 173 has first end 176 and second end 177, opposite first end
176.
Cartridge housing 173 is configured to receive cartridge tube 302, having
interior 303,
filled with flowable material 308. Plunger 175 is selectively translatable
within
cartridge tube 302 once cartridge tube 302 is received in cartridge housing
173 and
plunger 175 is received within cartridge tube 302. The preceding subject
matter of this
paragraph characterizes example 2 of the present disclosure, wherein example 2
also
includes the subject matter according to example 1, above.
Cartridge housing 173 receives and encloses cartridge tube 302. Furthermore,
cartridge housing 173 supports cartridge tube 302 while flowable material 308
is
dispensed from cartridge tube 302. During dispensing, plunger 175 is
positioned
within interior 303 of cartridge tube 302 and hydraulically forced to
translate from first
.. end 176 to second end 177. As plunger 175 translates from first end 176 to
second
end 177, plunger 175 displaces flowable material 308 from cartridge tube 302
at
second end 177 of cartridge housing 173. The controlled rotation of rotary
actuator
120 causes plunger 175 to translate within cartridge tube 302 because of the
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hydraulic coupling between reservoir 140 and flowable-material dispenser 160.
The
precision and control of rotary actuator 120 translates into precise and
controlled
dispensing of flowable material 308.
In one or more examples, the length of cartridge housing 173, between first
end 176 and second end 177, corresponds to the length of cartridge tube 302.
When
cartridge tube 302 is inserted into cartridge housing 173, the leading end of
cartridge
tube 302 is sealed against second end-cap 172 of apparatus 100. Second end-cap
172 is positioned at second end 177 of cartridge housing 173. In a similar
manner,
the lagging end of cartridge tube 302 is sealed against end-cap 171 of
apparatus 100,
positioned at first end 176 of cartridge housing 173.
In one or more examples, the inside diameter of cartridge housing 173
corresponds to the outside diameter of cartridge tube 302. As a result,
cartridge
tube 302 snuggly fits inside cartridge housing 173. In these examples, the
wall of
cartridge housing 173 supports the wall of cartridge tube 302 when the
hydraulic
pressure is applied to plunger 175 and also to the walls of cartridge tube
302, either
directly by hydraulic fluid 155 or by flowable material 308. This feature
allows using
cartridge tube 302 with a thin wall and/or applying high hydraulic pressures
(e.g., to
dispense particularly viscous materials and/or dispense at high rates).
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 2,
3A,
3B, and 4A-4D, plunger 175 is translatable within cartridge tube 302
responsive to
motion of piston 145 inside reservoir 140. The motion of piston 145 inside
reservoir
140 transfers hydraulic fluid 155 between reservoir 140 and cartridge housing
173 of
flowable-material dispenser 160. The preceding subject matter of this
paragraph
characterizes example 3 of the present disclosure, wherein example 3 also
includes
the subject matter according to example 2, above.
The hydraulic coupling between reservoir 140 and cartridge tube 302 enables
the position of plunger 175 in cartridge tube 302 to be controlled with piston
145
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inside reservoir 140, which in turn is controlled by rotary actuator 120.
Specifically,
the volume of hydraulic fluid 155 displaced from reservoir 140 (due to the
motion of
piston 145 inside reservoir 140) is the same as the volume of hydraulic fluid
155
received in cartridge tube 302 since hydraulic fluid 155 is not compressible.
This
volume of hydraulic fluid 155 received in cartridge tube 302 pushes plunger
175 from
first end 176 and second end 177.
A process of retraction of plunger 175 from cartridge tube 302 is similar. The
volume of hydraulic fluid 155 received into reservoir 140 due to the motion of
piston
145 inside reservoir 140 is the same as the volume of hydraulic fluid 155
transferred
from cartridge tube 302. This removal of hydraulic fluid 155 from cartridge
tube 302
between plunger 175 and first end 176 creates a negative pressure in hydraulic
fluid
155, which applies a force to plunger 175 toward first end 176. As a result of
this
negative pressure, plunger 175 is pushed from second end 177 to first end 176.
The translation distance of plunger 175 is proportional to the volume of
hydraulic fluid 155, transferred into or from cartridge tube 302.
Specifically, the
translation distance of plunger 175 is equal to the ratio of the volume of
hydraulic
fluid 155, transferred into or from cartridge tube 302, to the cross-sectional
area of
interior 303 of cartridge tube 302. As described above, the volume of
hydraulic
fluid 155 transferred to or from cartridge tube 302 is the same as the volume
of
hydraulic fluid 155 transferred from or to reservoir 140. Furthermore, the
volume of
hydraulic fluid 155 transferred to from cartridge tube 302 is the same as the
volume of
flowable material 308 dispensed by apparatus 100, assuming that flowable
material
308 and plunger 175 are not compressible. This transferred volume is
controlled by
rotary actuator 120 via gear train 125 and linear actuator 130.
In one or more examples, plunger 175 is translatable within cartridge tube 302
while being sealed against the interior surface of cartridge tube 302. For
example,
plunger 175 is formed from an elastomeric material (e.g., rubber). A portion
of
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plunger 175 is in direct contact with hydraulic fluid 155. In one or more
examples, this
portion of plunger 175 is always in direct contact with hydraulic fluid 155.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 2,
4A,
4C, 4D, 5A, and 5B, apparatus 100 further comprises end-cap 171, movably
coupled
with flowable-material dispenser 160 at first end 176 of cartridge housing
173,
hydraulically coupled with reservoir 140, and configured to selectively
sealingly
engage interior 303 of cartridge tube 302 when cartridge tube 302 in received
within
cartridge housing 173 of flowable-material dispenser 160. The preceding
subject
matter of this paragraph characterizes example 4 of the present disclosure,
wherein
example 4 also includes the subject matter according to example 2 or 3, above.
When end-cap 171 seals against interior 303 of cartridge tube 302, a
combination of end-cap 171, plunger 175, and cartridge tube 302 defines the
volume
of hydraulic fluid 155 within interior 303 of cartridge tube 302. As described
above,
when hydraulic fluid 155 is transferred into cartridge tube 302, this volume
increases.
Specifically, hydraulic fluid 155 translates plunger 175 away from end-cap
171. On
the other hand, when hydraulic fluid 155 is transferred back in reservoir 140,
this
volume decreases. During this operation, hydraulic fluid 155 is at a negative
pressure
and pulls plunger 175 within cartridge tube 302 toward end-cap 171.
End-cap 171 is movably coupled to flowable-material dispenser 160. In one
position, shown in FIGS. 4A, 4C, 4D, and 5B, end-cap 171 sealingly engages
interior
303 of cartridge tube 302. In this position, plunger 175 is disposed within
cartridge
tube 302 and is translatable within cartridge tube 302 by flowing hydraulic
fluid 155
through end-cap 171. In another position, shown in FIG. 5A, end-cap 171 is
positioned away from first end 176 of cartridge housing 173. In this position,
cartridge
housing 173 is accessible to remove or install cartridge tube 302 inside
cartridge
housing 173.
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The seal between end-cap 171 and interior 303 of cartridge tube 302 ensures
that hydraulic fluid 155 stays within interior 303 of cartridge tube 302 and
does not
leak from cartridge tube 302 into cartridge housing 173. The seal is
maintained while
end-cap 171 is positioned at first end 176 of cartridge housing 173. The seal
is
broken when end-cap 171 is moved away from first end 176 of cartridge housing
173
as shown, for example, in FIG. 5A.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4A,
4C,
and 4D, end-cap 171 comprises first gasket 421, configured to selectively seal
against interior 303 of cartridge tube 302 when cartridge tube 302 is received
within
cartridge housing 173. The preceding subject matter of this paragraph
characterizes
example 5 of the present disclosure, wherein example 5 also includes the
subject
matter according to example 4, above.
First gasket 421 is sealed against interior 303 of cartridge tube 302 to
ensure
that hydraulic fluid 155 stays within cartridge tube 302 and does not leak out
of
cartridge tube 302, e.g., into cartridge housing 173. As hydraulic fluid 155
is supplied
into cartridge tube 302, plunger 175 translates from first end 176 to second
end 177
of cartridge housing 173 and displaces flowable material 308 from cartridge
tube 302.
Preventing loss of hydraulic fluid 155 from cartridge tube 302 ensures
dispensing
precision.
Referring to FIGS. 4C and 4D, in one or more examples, first gasket 421 is an
0-ring. In the same or other examples, first gasket 421 is positioned in a
channel of
end-cap 171. The outer diameter of first gasket 421 is greater than the inner
diameter of cartridge tube 302, which provides interference fit and sealing.
In one or
more examples, first gasket 421 is formed from an elastomeric material (e.g.,
rubber).
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4C
and
4D, flowable-material dispenser 160 further comprises second gasket 422,
configured
to seal end-cap 171 against plunger 175 when a sufficient amount of hydraulic
fluid
CA 3052166 2019-08-14
155 is transferred from cartridge housing 173 to reservoir 140 to cause
plunger 175 to
abut end-cap 171 and an additional amount of hydraulic fluid 155 is
subsequently
transferred from cartridge housing 173 to reservoir 140. The preceding subject
matter
of this paragraph characterizes example 6 of the present disclosure, wherein
example
6 also includes the subject matter according to example 5, above.
Second gasket 422 forms a seal between plunger 175 and end-cap 171, which
in turn allows creating a negative pressure (relative to the atmosphere) in
hydraulic
fluid 155. This negative pressure forces plunger 175 against end-cap 171
allowing,
for example, removal of plunger 175 from cartridge tube 302. Furthermore, this
negative pressure supports plunger 175 on end-cap 171 after plunger 175 is
removed
from cartridge tube 302.
In one or more examples, second gasket 422 is attached to end-cap 171, as
shown in FIG. 4D. For example, second gasket 422 is glued to a surface of end-
cap
171 or positioned in a groove formed in end-cap 171. Second gasket 422
protrudes
from the surface of end-cap 171 and, in one or more examples, directly
contacts
plunger 175 when plunger 175 is supported by end-cap 171. Alternatively,
second
gasket 422 is a part of or is attached to plunger 175. In one or more
examples,
second gasket 422, shown in FIG. 4D, is formed from an elastomeric material
(e.g.,
rubber).
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4C
and
4D, end-cap 171 further comprises annular boss 427. Plunger 175 comprises
annular recess 429. Annular boss 427 and annular recess 429 have complementary
shapes. The preceding subject matter of this paragraph characterizes example 7
of
the present disclosure, wherein example 7 also includes the subject matter
according
to example 5 or 6, above.
Inserting annular boss 427 of end-cap 171 into annular recess 429 of plunger
175 provides interference fit and/or frictional fit between end-cap 171 and
plunger
16
CA 3052166 2019-08-14
175. This fit provides support to plunger 175 relative to end-cap, in addition
to or
instead of support provided by the negative pressure of hydraulic fluid 155,
as
described above. Furthermore, a combination of annular boss 427 of end-cap 171
and annular recess 429 of plunger 175 is used to control orientation of
plunger 175
relative to end-cap 171 when plunger 175 is extracted from cartridge tube 302.
This
orientation control allows removal of plunger 175 from end-cap 171and
reinstallation
of plunger 175 onto end-cap 171, e.g., during initial assembly of apparatus
100,
cleaning and maintenance of apparatus 100, and other like tasks.
In one or more examples, annular boss 427 comprises a fillet or a chamfer for
directing and/or centering annular recess 429 relative to annular boss 427.
Likewise,
in one or more examples, annular recess 429 comprises a fillet or a chamfer
for
locating annular boss 427 relative to annular recess 429 and for guiding the
rest of
annular boss 427 into annular recess 429.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4C
and
4D, apparatus 100 further comprises second gasket 422 between annular boss 427
of end-cap 171 and annular recess 429 of plunger 175. The preceding subject
matter
of this paragraph characterizes example 8 of the present disclosure, wherein
example
8 also includes the subject matter according to example 7, above.
Second gasket 422 forms a seal between plunger 175 and end-cap 171, which
in turn allows creating a negative pressure (relative to the atmosphere) in
hydraulic
fluid 155. This negative pressure creates a force, applied to plunger 175
against end-
cap 171, which in turn allows removing plunger 175 from cartridge tube 302.
The
negative pressure is also used for supporting plunger 175 on end-cap 171,
after
plunger 175 is removed from cartridge tube 302. Annular boss 427 of end-cap
171
and annular recess 429 of plunger 175 have complementary shapes such that
their
mating surfaces contact each other when annular boss 427 is inserted into
annular
recess 429. Second gasket 422 establishes a seal between these mating
surfaces.
17
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In one or more examples, shown in FIG. 4D, second gasket 422 is attached to
end-cap 171. For example, second gasket 422 is glued to a surface of end-cap
171
or is positioned in a groove formed in end-cap 171. Second gasket 422
protrudes
from the surface of end-cap 171 and, in one or more examples, directly
contacts
plunger 175 when plunger 175 is supported by end-cap 171. In one or more
examples, second gasket 422, shown in FIG. 4D, is formed from an elastomeric
material (e.g., rubber).
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4C,
4D,
5A and 5B, apparatus 100 further comprises over-center mechanism 179, movably
coupling end-cap 171 with cartridge housing 173 of flowable-material dispenser
160
and configured to selectively retain end-cap 171 relative to cartridge housing
173
such that end-cap 171 sealingly engages interior 303 of cartridge tube 302,
received
within cartridge housing 173, and to selectively remove end-cap 171 from
cartridge
tube 302, received within cartridge housing 173. The preceding subject matter
of this
paragraph characterizes example 9 of the present disclosure, wherein example 9
also
includes the subject matter according to any one of examples 4 to 8, above.
Over-center mechanism 179 is attached to end-cap 171 and is used to move
end-cap 171 relative to cartridge housing 173 between at least two positions.
In one
position, end-cap 171 is positioned at first end 176 of cartridge housing 173
and
sealingly engages interior 303 of cartridge tube 302 as shown, for example, in
FIG.
4C. In the other position, end-cap 171 is positioned away from cartridge
housing 173
as shown, for example, in FIG. 5B. In this other position, first end 176 of
cartridge
housing 173 is accessible, which allows removing, replacing, and/or installing
cartridge tube 302.
In some examples, over-center mechanism 179 is attached to and supported
on cartridge housing 173. End-cap 171 is movable by over-center mechanism 179
relative to cartridge housing 173 as shown, for example, in FIGs. 5A and 5B.
In some
examples, over-center mechanism 179 comprises multiple arms pivotably coupled
to
18
CA 3052166 2019-08-14
each other. The number and the length of these arms establish the trajectory
of end-
cap 171 when end-cap 171 is moved by over-center mechanism 179 between at
least
the two positions of end-cap 171. In one or more examples, the movement of end-
cap 171 relative to cartridge housing 173 is substantially along the center
axis of
cartridge housing 173 when end-cap 171 approaches first end 176 of cartridge
housing 173. As described above, end-cap 171 supports plunger 175, and plunger
175 is inserted into cartridge tube 302 when end-cap 171 approaches first end
176 of
cartridge housing 173.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 5A
and
5B, apparatus 100 further comprises first double-acting pneumatic cylinder
510,
operatively coupling over-center mechanism 179 with cartridge housing 173 of
flowable-material dispenser 160. The preceding subject matter of this
paragraph
characterizes example 10 of the present disclosure, wherein example 10 also
includes the subject matter according to example 9, above.
First double-acting pneumatic cylinder 510 is connected to and is used to move
one end of over-center mechanism 179. The other end of over-center mechanism
179 is coupled to end-cap 171. This movement of first double-acting pneumatic
cylinder 510 causes the movement of end-cap 171 relative to cartridge housing
173
between at least two positions, described above. First double-acting pneumatic
cylinder 510 enables automation of this operation.
The force applied by first double-acting pneumatic cylinder 510 to over-center
mechanism 179 in one direction ensures that plunger 175 and a portion of end-
cap
171 is inserted into cartridge tube 302 as shown, for example, in FIG. 4C. The
force
applied by first double-acting pneumatic cylinder 510 to over-center mechanism
179
in the opposite direction ensures that plunger 175 is extracted from interior
303 of
cartridge tube 302. The travel length of first double-acting pneumatic
cylinder 510 is
such that end-cap 171 is positioned away from cartridge housing 173 as shown,
for
example, in FIG. 5B. In this position, end-cap 171 and plunger 175 do not
interfere
19
CA 3052166 2019-08-14
with access to first end 176 of cartridge housing 173, which allows removing,
replacing, and/or installing cartridge tube 302.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIG. 4E,
flowable-material dispenser 160 further comprises second end-cap 172, located
opposite end-cap 171 at second end 177 of cartridge housing 173 of flowable-
material dispenser 160 and configured to seal against cartridge tube 302 when
cartridge tube 302 is within cartridge housing 173 and end-cap 171 is retained
relative
to cartridge housing 173 such that end-cap 171 sealingly engages interior 303
of
cartridge tube 302. The preceding subject matter of this paragraph
characterizes
example 11 of the present disclosure, wherein example 11 also includes the
subject
matter according to any one of examples 4 to 10, above.
The seal between second end-cap 172 and cartridge tube 302 ensures that
flowable material 308 is directed from cartridge tube 302 through second end-
cap 172
and toward the dispensing tip of flowable-material dispenser 160. Furthermore,
this
seal ensures that flowable material 308 does not flow into the space between
cartridge tube 302 and cartridge housing 173, thereby preventing contamination
of
cartridge housing 173. The seal is established when cartridge tube 302 is
inserted
into cartridge housing 173 and maintained until cartridge tube 302 is removed
from
cartridge housing 173.
In some examples, as shown in FIG. 4E, second end-cap 172 comprises
gasket 163 for sealing against cartridge tube 302.
When cartridge tube 302 is
inserted into cartridge housing 173, the leading end of cartridge tube 302 is
pressed
against gasket 163, establishing the seal. Gasket 163 is formed from an
elastomeric
material (e.g., rubber). As shown in FIG. 4E, a sealing portion of second end-
cap 172
overlaps with cartridge tube 302 or, more specifically, with the leading end
of
cartridge tube 302, for additional sealing and/or maintaining orientation of
cartridge
tube 302. For example, this sealing portion of second end-cap 172 protrudes
into
cartridge tube 302.
CA 3052166 2019-08-14
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIG. 4E,
flowable-material dispenser 160 further comprises cartridge-ejection inlet
530,
pneumatically coupled with second end-cap 172 to selectively supply compressed
fluid inside cartridge housing 173 of flowable-material dispenser 160 for
ejecting
cartridge tube 302 from cartridge housing 173 when end-cap 171 is removed from
cartridge tube 302, received within cartridge housing 173. The preceding
subject
matter of this paragraph characterizes example 12 of the present disclosure,
wherein
example 12 also includes the subject matter according to example 11, above.
Cartridge-ejection inlet 530 is used to break the seal between second end-cap
172 and cartridge tube 302 and remove cartridge tube 302 from cartridge
housing
173. In one or more examples, access to cartridge tube 302 from first end 176
of
cartridge housing 173 is limited. For instance, FIG. 4C and 4D illustrate only
a small
portion of cartridge tube 302 protruding from cartridge housing 173 at first
end 176 of
cartridge housing 173. Specifically, the flow of the compressed fluid
(e.g.,
compressed air) through cartridge-ejection inlet 530 into cartridge housing
173, at a
location close to second end-cap 172, increases the pressure inside cartridge
housing 173 at second end 177. This pressure forces plunger 175 away from
second
end-cap 172. The gap between cartridge housing 173 and cartridge tube 302 is
minimal (e.g., less than 1 millimeter) to pressurize an area inside cartridge
housing
173, at least near second end-cap 172.
In one or more examples, the outer diameter of cartridge tube 302 is
substantially the same as the inner diameter of cartridge housing 173 (e.g.,
within
10% or within 5%). As such, the compressed fluid cannot easily escape between
cartridge tube 302 and cartridge housing 173 when compressed gas is supplied
into
cartridge housing 173 at a location close to second end-cap 172. In one or
more
examples, cartridge-ejection inlet 530 comprises a valve and a coupling to a
source of
the compressed fluid, such as compressed air. More specifically, the operation
of
cartridge-ejection inlet 530 is synchronized with operation of other
components of
apparatus 100, such as over-center mechanism 179. For example, cartridge-
ejection
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CA 3052166 2019-08-14
inlet 530 supplies the compressed fluid inside cartridge housing 173 only
after over-
center mechanism 179 moves end-cap 171 away from second end 177 of cartridge
housing 173, thereby allowing cartridge tube 302 to be removed from cartridge
housing 173.
Referring generally to FIGS. IA and 1B, and particularly to, e.g., FIG. 4E,
flowable-material dispenser 160 further comprises vent 162, located at second
end
177 of cartridge housing 173. Vent 162 is configured to admit atmosphere into
cartridge tube 302, received inside cartridge housing 173, as plunger 175 is
retracted
within cartridge tube 302 from second end 177 of cartridge housing 173 toward
first
end 176 of cartridge housing 173. The preceding subject matter of this
paragraph
characterizes example 13 of the present disclosure, wherein example 13 also
includes the subject matter according to example 11 or 12, above.
When plunger 175 is moved within cartridge tube 302 from first end 176 to
second end 177 of cartridge housing 173, flowable material 308 is dispensed
from
cartridge tube 302. Vent 162 is closed during this operation to prevent
flowable
material 308 from escaping through vent 162. On the other hand, when plunger
175
is retracted within cartridge tube 302 from second end 177 to first end 176,
the
volume inside cartridge tube 302, previously occupied by flowable material
308,
needs to be backfilled. If the volume is not backfilled, the excessive
negative
pressure within cartridge tube 302, between plunger 175 and the dispensing
nozzle,
will prevent plunger 175 from being moved within cartridge tube 302.
Furthermore,
this negative pressure can pull a portion of flowable material 308, remaining
in
apparatus 100 (e.g., in the dispensing nozzle), back into cartridge tube 302.
During
this plunger extraction operation, vent 162 is open and admits the atmosphere
into
cartridge tube 302. Cartridge tube 302 is effectively backfilled, which allows
effortless
movement of plunger 175 within cartridge tube 302 from second end 177 toward
first
end 176 of cartridge housing 173.
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In one or more examples, vent 162 comprises a valve, one end of which is in
fluid communication with interior 303 of cartridge tube 302 (when cartridge
tube 302 is
positioned inside cartridge housing 173). The other end of this valve is open
to the
atmosphere. In one or more examples, the operation of vent 162 is synchronized
with
the operation of other components of apparatus 100, such as rotary actuator
120.
Specifically, vent 162 allows the atmosphere into cartridge tube 302 when
rotary
actuator 120 is turning in second rotational direction 122, resulting in
hydraulic fluid
155 being transferred from flowable-material dispenser 160 to reservoir 140.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIG. 4E,
vent
162 is further configured to admit atmosphere into cartridge tube 302,
received inside
cartridge housing 173, as plunger 175 is extracted from cartridge tube 302 by
end-
cap 171. The preceding subject matter of this paragraph characterizes example
14 of
the present disclosure, wherein example 14 also includes the subject matter
according to example 13, above.
When plunger 175 is retracted within cartridge tube 302 from second end 177
to first end 176 and later extracted from cartridge tube 302, the volume
inside
cartridge tube 302, previously occupied by flowable material 308, needs to be
backfilled to avoid excessive negative pressure within cartridge tube 302. If
the
volume is not backfilled, the excessive negative pressure will prevent plunger
175
from being extracted from cartridge tube 302.
In one or more examples, the backfill continues as plunger 175 is completely
extracted from cartridge tube 302 by end-cap 171. Overall, the force acting on
plunger 175 and created by the negative pressure of hydraulic fluid 155,should
be
greater than the friction force between plunger 175 and cartridge tube 302 and
should
also exceed any negative pressure within cartridge tube 302 between plunger
175
and the dispensing nozzle. Backfilling through vent 162 allows reducing this
negative
pressure within cartridge tube 302 between plunger 175 and the dispensing
nozzle.
23
CA 3052166 2019-08-14
In one or more examples, the operation of vent 162 is synchronized with
operation of other components of apparatus 100, such as over-center mechanism
179 or, more specifically, first double-acting pneumatic cylinder 510,
operatively
coupled to over-center mechanism 179. Specifically, vent 162 allows the
atmosphere
into cartridge tube 302 when over-center mechanism 179 moves end-cap 171 away
from first end 176 of cartridge housing 173, thereby extracting plunger 175
from
cartridge tube 302. It should be noted that plunger 175 is supported on end-
cap 171
during this operation by the negative pressure of hydraulic fluid 155.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4C
and
4D, piston 145 comprises third gasket 423, configured to seal against
cartridge tube
302. The preceding subject matter of this paragraph characterizes example 15
of the
present disclosure, wherein example 15 also includes the subject matter
according to
any one of examples 2 to 14, above.
Sealing third gasket 423 of piston 145 against cartridge tube 302 allows
pressurizing hydraulic fluid 155, particularly in a volume between piston 145
and end-
cap 171, as shown in FIG. 4D. This seal prevents hydraulic fluid 155 from
leaking
past piston 145 and from contacting flowable material 308 inside cartridge
tube 302.
At the same time, the pressure is needed to advance piston 145 from first end
176 to
second end 177 of cartridge housing 173 and displace flowable material 308
from
cartridge tube 302. Furthermore, this seal prevents air being introduced into
the pool
of hydraulic fluid 155, which is positioned between piston 145 and end-cap 171
when
piston 145 is extracted from cartridge tube 302 (e.g., pulled by the negative
pressure
of hydraulic fluid 155 from second end 177 to first end 176 of cartridge
housing 173).
Third gasket 423 allows piston 145 to move within cartridge tube 302 while
maintaining the seal against cartridge tube 302.
In one or more examples, third gasket 423 is formed from an elastomeric
material (e.g., rubber). In the same or other examples, third gasket 423 is
positioned
in an annular groove of piston 145 and protrudes past the surface of piston
145,
24
CA 3052166 2019-08-14
adjacent to the annular groove, to form interference fit with interior 303 of
cartridge
tube 302.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 4B
and
4C, cartridge tube 302 comprises cartridge plunger 304, comprising rear
surface 305
and front surface 301, opposite rear surface 305. Plunger 175 comprises thrust
surface 178, complementary in shape to rear surface 305 of cartridge plunger
304.
The preceding subject matter of this paragraph characterizes example 16 of the
present disclosure, wherein example 16 also includes the subject matter
according to
any one of examples 2 to 15, above.
Cartridge plunger 304 seals flowable material 308 within interior 303 of
cartridge tube 302 prior to installation of cartridge tube 302 into cartridge
housing 173.
Once cartridge tube 302 is installed in cartridge housing 173 and plunger 175
is
inserted into cartridge tube 302, cartridge plunger 304 separates plunger 175
from
flowable material 308, thereby preventing any direct contact between plunger
175 and
flowable material 308 and contamination of plunger 175. Cartridge plunger 304
is
advanced by plunger 175 from one end of cartridge tube 302, proximate to first
end
176 of cartridge housing 173, to another end of cartridge tube 302, proximate
to
second end 177 of cartridge housing 173. During this operation, thrust surface
178 of
plunger 175 is pressed against rear surface 305 of cartridge plunger 304. The
complementary shapes of rear surface 305 of cartridge plunger 304 and thrust
surface 178 of plunger 175 ensure that the original or working shape of
cartridge
plunger 304 is preserved and that cartridge plunger 304 continues to separate
plunger 175 from flowable material 308.
In one or more examples, cartridge plunger 304 is flexible or, more
specifically,
deformable. In these examples, rear surface 305 of cartridge plunger 304
becomes
complementary in shape to thrust surface 178 of plunger 175 when rear surface
305
of cartridge plunger 304 is contacted by thrust surface 178 of plunger 175 and
while
plunger 175 advances cartridge plunger 304 within cartridge tube 302. In one
or
CA 3052166 2019-08-14
more examples, both rear surface 305 of cartridge plunger 304 and thrust
surface 178
of plunger 175 have a dome shape.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 6A
and
6B, flowable-material dispenser 160 further comprises dispenser valve 600,
located
at second end 177 of cartridge housing 173, and second double-acting pneumatic
cylinder 520, configured to selectively open or close dispenser valve 600. The
preceding subject matter of this paragraph characterizes example 17 of the
present
disclosure, wherein example 17 also includes the subject matter according to
any one
of examples 2 to 16, above.
Dispenser valve 600 controls the flow of flowable material 308 from apparatus
100. This control is used in addition to control provided by rotary actuator
120.
Furthermore, when dispenser valve 600 is closed, flowable material 308, which
remains in flowable-material dispenser 160, is isolated from the environment
(e.g., to
prevent curing of the remaining portion of flowable material 308 that is still
inside
flowable-material dispenser 160). When dispenser valve 600 is open, flowable
material 308 passes through dispenser valve 600 and is dispensed from
apparatus
100. In one or more examples, a combination of dispenser valve 600 and rotary
actuator 120 is used to control the pressure of hydraulic fluid 155, which in
turn
controls the flow rate of flowable material 308.
In one or more examples, dispenser valve 600 comprises stem 612, protruding
through pass-through 614 and supporting plug 610, as shown, for instance, in
FIGS.
6A and 6B. When plug 610 is pressed against pass-through 614 as shown, for
example, in FIG. 6A, dispenser valve 600 is closed and flowable material 308
cannot
pass through dispenser valve 600. On the other hand, when plug 610 is
positioned
away from pass-through 614 as shown, for example, in FIG. 6B, dispenser valve
600
is open and flowable material 308 is able to pass through dispenser valve 600.
In
one or more examples, dispenser valve 600 has one or more partially open
positions.
26
CA 3052166 2019-08-14
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 3A
and
3B, linear actuator 130 comprises screw 135, ball nut 134, and plurality of
balls 133,
threadably coupling screw 135 and ball nut 134. Screw 135 has central axis 131
and
is coupled to piston 145. Ball nut 134 is coupled to one of gears in gear
train 125.
The preceding subject matter of this paragraph characterizes example 18 of the
present disclosure, wherein example 18 also includes the subject matter
according to
any one of examples Ito 17, above.
A combination of screw 135, ball nut 134, and plurality of balls 133 in linear
actuator 130 translates the rotation of ball nut 134, which is driven by gear
train 125,
into the linear motion of screw 135, which is coupled to piston 145. As such,
the
precise rotation of rotary actuator 120, through gear train 125 to ball nut
134, is
translated in the precise linear motion of screw 135 and, more specifically,
of piston
145. The linear motion of piston 145 within reservoir 140 results in the
precise
transfer of hydraulic fluid 155 between reservoir 140 and flowable-material
dispenser
160, which in turn results in the precise dispensing of flowable material 308.
In one or more examples, screw 135 is a threaded shaft, which provides a
helical raceway for a plurality of balls 133. Linear actuator 130 is able to
apply or
withstand high thrust loads (e.g., for dispensing flowable materials 308 that
have high
viscosities) with minimum internal friction. Close tolerances screw 135, ball
nut 134,
and plurality of balls 133 provide high precision with minimal friction.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 3B-
3D,
linear actuator 130 comprises housing 138 and anti-rotation mechanism 139,
coupled
to housing 138 and slidably coupled to screw 135. Anti-rotation mechanism
prevents
screw 135 from rotating around central axis 131 of screw 135 relative to
housing 138.
Housing is stationary relative to rotary actuator 120. The preceding subject
matter of
this paragraph characterizes example 19 of the present disclosure, wherein
example
19 also includes the subject matter according to example 18, above.
27
CA 3052166 2019-08-14
Anti-rotation mechanism 139 ensures that screw 135 does not rotate relative to
housing 138 around central axis 131 of screw 135. As such, anti-rotation
mechanism
139 ensures the exact relationship between the rotation of ball nut 134 and
the linear
motion of screw 135. This relationship is provided by the thread pitch of ball
nut 134
and screw 135, which is fixed, and the rotation of ball nut 134 relative to
screw 135
around central axis 131 of screw 135. Thus, by preventing screw 135 from
rotating,
the rotation of ball nut 134 provides the exclusive control of this linear
motion, thereby
ensuring the precise dispensing of flowable material 308.
The thread pitch of ball nut 134 and screw 135 is, for example, between
0.1 millimeters and 10 millimeters or, more specifically, between 0.5
millimeters and
3 millimeters. For example, a thread pitch of 1 millimeter results in a 1
millimeter
linear motion of screw 135 for each rotation of ball nut 134 relative to screw
135.
Since ball nut 134 does not rotate around central axis 131, the rotation of
ball nut 134
controls this linear motion.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 3B
and
3C, screw 135 comprises slot 192. Anti-rotation mechanism 139 comprises
protrusion 191, extending into slot 192 of screw 135. Slot 192 extends along
central
axis 131 of screw 135. The preceding subject matter of this paragraph
characterizes
example 20 of the present disclosure, wherein example 20 also includes the
subject
matter according to example 19, above.
Protrusion 191 is coupled to housing 138 and extends into slot 192 of screw
135. As such, screw 135 is not able to rotate around central axis 131 relative
to
housing 138. Preventing the rotation of screw 135, provided by protrusion 191
and
slot 192, ensures the exclusive control of the linear translation of screw 135
by the
rotation of ball nut 134. Slot 192, extending along central axis 131 of screw
135,
enables screw 135 to linearly move relative to protrusion 191 and relative to
housing
138, so that piston 145 is linearly advanced inside reservoir 140.
28
CA 3052166 2019-08-14
In some examples, protrusion 191 is a set screw, threaded into housing 138.
In these examples, protrusion 191 is adjustable relative to screw 135 (e.g.,
to extend
into slot 192 during operation of apparatus 100 or to retract from slot 192
during
disassembly of apparatus 100). In one or more examples, slot 192 has two
parallel
walls, extending along central axis 131, as shown, for example, in FIG. 3C.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 3B
and
3D, screw 135 comprises first surface 193. Anti-rotation mechanism 139
comprises
second surface 194, slidably contacting first surface 193 of screw 135 at at
least two
points of first surface 193 that lie on opposite sides of orthogonal
projection 132 of
central axis 131 onto first surface 193. The preceding subject matter of this
paragraph
characterizes example 21 of the present disclosure, wherein example 21 also
includes the subject matter according to example 19, above.
The slidable contact between second surface 194 and first surface 193
enables screw 135 to linearly translate relative to housing 138 along central
axis 131.
At the same time, since contact exists between second surface 194 and first
surface
193 at at least two points that lie on opposite sides of orthogonal projection
132 of
central axis 131 onto first surface 193, rotation of screw 135 relative to
second
surface 194 and relative to housing 138 is prevented, ensuring exclusive
control of
the linear translation of screw 135 by the rotation of ball nut 134.
In one or more examples, first surface 193 and second surface 194 are
conformal surfaces or, more specifically, planar surfaces as shown, for
example, in
FIG. 3D. However, other types of surfaces that contact each other at at least
two
points that lie on opposite sides of orthogonal projection 132 of central axis
131 are
also within the scope of the present disclosure.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIGS. 3E
and
3F piston 145 and reservoir 140 have complementary, non-circular cross-
sections.
The preceding subject matter of this paragraph characterizes example 22 of the
29
CA 3052166 2019-08-14
present disclosure, wherein example 22 also includes the subject matter
according to
any one of examples 1 to 18, above.
The non-circular aspect of the complementary non-circular cross-sections of
piston 145 and reservoir 140 prevents rotation of piston 145 around central
axis 131
relative to reservoir 140. Piston 145 is also coupled to screw 135, which, as
a result
of this coupling, also does not rotate around central axis 131 relative to
reservoir 140
or, more specifically, relative to housing 138. Preventing the rotation of
screw 135
ensures the exclusive control of the linear translation of screw 135 by the
rotation of
ball nut 134. However, piston 145 is allowed to linearly translate relative to
reservoir
140 along central axis 131. Furthermore, the complementary aspect of the non-
circular cross-sections establishes a seal between piston 145 and reservoir
140 such
that hydraulic fluid 155 does not leak past piston 145 during operation of
apparatus
100.
The complementary non-circular cross-sections of piston 145 and reservoir
140 have any shape that is different from that of a circle. Any such shape
will prevent
rotation of piston 145 relative to reservoir 140. FIG. 3E illustrates an
example of an
oval shape, while FIG. 3F illustrates an example of a rectangular shape. In
one or
more examples, at least one gasket is positioned at the interface of piston
145 and
reservoir 140.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIG. 3E,
the
complementary non-circular cross-sections are oval. The preceding subject
matter of
this paragraph characterizes example 23 of the present disclosure, wherein
example
23 also includes the subject matter according to example 22, above.
The oval shapes of the complementary non-circular cross-sections of piston
145 and reservoir 140 prevent rotation of piston 145 around central axis 131
relative
to reservoir 140. Piston 145 is also coupled to screw 135, which, as a result
of this
coupling, also does not rotate around central axis 131 relative to reservoir
140 or,
'
CA 3052166 2019-08-14
more specifically, relative to housing 138. Preventing the rotation of screw
135
ensures the exclusive control of the linear translation of screw 135 by the
rotation of
ball nut 134. However, piston 145 is allowed to linearly translate relative to
reservoir
140 along central axis 131. Furthermore, the complementary aspect of the oval
cross-sections establishes a seal between piston 145 and reservoir 140 such
that
hydraulic fluid 155 does not leak past piston 145 during operation of
apparatus 100.
The oval shape, or any other shape without sharp corners, allows using a
continuous seal, thereby sealing the interface between piston 145 and
reservoir 140.
Furthermore, fabrication of pistons and reservoirs having oval shapes is
generally
simpler than that of parts having shapes with sharp corners.
Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIG. 3F, the
complementary non-circular cross-sections are rectangular. The preceding
subject
matter of this paragraph characterizes example 24 of the present disclosure,
wherein
example 24 also includes the subject matter according to example 22, above.
The rectangular shape of complementary non-circular cross-sections of piston
145 and reservoir 140 prevents rotation of piston 145 around central axis 131
relative
to reservoir 140. Piston 145 is also coupled to screw 135, which, as a result
of this
coupling, also does not rotate around central axis 131 relative to reservoir
140 or,
more specifically, relative to housing 138. Preventing the rotation of screw
135
ensures the exclusive control of the linear translation of screw 135 by the
rotation of
ball nut 134. However, piston 145 is allowed to linearly translate relative to
reservoir
140 along central axis 131.
Furthermore, the complementary aspect of the
rectangular cross-sections establishes a seal between piston 145 and reservoir
140
such that hydraulic fluid 155 does not leak past piston 145 during operation
of
apparatus 100.
The rectangular shape, or any other shape with sharp corners, is able to
withstand large torques applied to piston 145, e.g., when linear actuator 130
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experiences friction or when piston 145 reaches an end point and further
motion is
not possible. For example, rotary actuator 120 is automatically shut down when
experiencing a torque spike (e.g., when piston 145 reaches the end of its
travel).
However, other components of apparatus 100 should be able to withstand this
torque
as well.
Referring generally to FIGS. 1A and 1B, and particularly to, e.g., FIG. 2,
apparatus 100 further comprises conduit 150, hydraulically coupling flowable-
material
dispenser 160 with reservoir 140. The preceding subject matter of this
paragraph
characterizes example 25 of the present disclosure, wherein example 25 also
includes the subject matter according to any one of examples 1 to 24, above.
Conduit 150 allows separation and different orientations of flowable-material
dispenser 160 and reservoir 140 relative to each other. As a result, apparatus
100 is
more compact than it would have been if, for instance, flowable-material
dispenser
160 were directly coupled to reservoir 140. For example, FIG. 2 illustrates
flowable-
material dispenser 160 and reservoir 140 positioned along different axes.
In one or more examples, conduit 150 is flexible, which allows movement of
flowable-material dispenser 160 relative to reservoir 140. For example,
reservoir 140
is a part of stationary components of apparatus 100, while flowable-material
dispenser 160 is a movable component.
Referring generally to FIGS. 7A and 7B and particularly to, e.g., FIGS. 3A-3B,
4A-4D, 5A, 5B, method 700 for dispensing flowable material 308 using apparatus
100
is disclosed. Apparatus 100 comprises rotary actuator 120, reservoir 140,
containing
hydraulic fluid 155, and piston 145, movable inside reservoir 140. Apparatus
100 also
comprises linear actuator 130, coupled to piston 145, and gear train 125,
coupling
rotary actuator 120 with linear actuator 130. Apparatus 100 additionally
comprises
flowable-material dispenser 160, comprising cartridge housing 173 and plunger
175
and hydraulically coupled with reservoir 140. Apparatus 100 further comprises
end-
32
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cap 171, movably coupled with flowable-material dispenser 160, and over-center
mechanism 179, movably coupling end-cap 171 with cartridge housing 173 of
flowable-material dispenser 160. Method 700 comprises (block 710)
holding
hydraulic fluid 155 in reservoir 140 at a negative pressure, sufficient to
generate a
vacuum between end-cap 171 and plunger 175, (block 720) inserting cartridge
tube
302, having interior 303, into cartridge housing 173, wherein flowable
material 308 is
inside cartridge tube 302, (block 730) locking over-center mechanism 179
relative to
cartridge housing 173 so that a hermetic seal is created between plunger 175
and
interior 303 of cartridge tube 302 and between end-cap 171 and interior 303 of
cartridge tube 302, and (block 740) turning rotary actuator 120 in rotational
direction
121 so that linear actuator 130 advances piston 145 within reservoir 140 to
transfer at
least a portion of hydraulic fluid 155 from reservoir 140 to flowable-material
dispenser
160 through end-cap 171 and into interior 303 of cartridge tube 302, causing
plunger
175 to advance within cartridge tube 302 in forward plunger direction 181,
away from
end-cap 171. The preceding subject matter of this paragraph characterizes
example
26 of the present disclosure.
When hydraulic fluid 155 is held at a negative pressure in reservoir 140, this
negative pressure is also present in all other areas of apparatus 100 occupied
by
hydraulic fluid 155. As a result, plunger 175, which contacts hydraulic fluid
155, is
forced by hydraulic fluid 155 toward and against end-cap 171. This force
supports
plunger 175 on end-cap 171 and allows positioning plunger 175 away from
cartridge
housing 173 when end-cap 171 is moved away from cartridge housing 173. This
position of plunger 175 and end-cap 171, away from cartridge housing 173,
provides
access to cartridge housing 173 allowing to insert cartridge tube 302 into
cartridge
housing 173 (block 720).
Referring to FIGS. 5A and 5B, one end of over-center mechanism 179 is
attached to end-cap 171. When over-center mechanism 179 is locked relative to
cartridge housing 173 as shown in FIG. 5B, plunger 175 is pressed by end-cap
171
into interior 303 and is hermetically sealed against interior 303 as shown in
FIG. 4C.
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The hermetic seal prevents flowable material 308 from flowing past plunger
175.
Furthermore, the hermetic seal prevents hydraulic fluid 155 from flowing past
plunger
175 and reaching flowable material 308. However, the seal allows plunger 175
to
advance within cartridge tube 302.
The other hermetic seal is formed between end-cap 171 and interior 303 of
cartridge tube 302. This other seal keeps hydraulic fluid 155 within interior
303 when
hydraulic fluid 155 is transferred into interior 303 and maintained at a
positive
pressure or at a negative pressure (e.g., to advance plunger 175 within
cartridge tube
302). This seal is maintained while end-cap 171 is positioned at first end 176
of
cartridge housing 173.
When rotary actuator 120 is turned in rotational direction 121, linear
actuator 130 advances piston 145 within reservoir 140, as schematically shown
in
FIG. 3B. The rotational speed and the degree of rotation of rotary actuator
120 are
precisely controlled. This control translates into the precise linear motion
of piston
145. As piston 145 moves within reservoir 140, at least a portion of hydraulic
fluid
155 is transferred from reservoir 140 to flowable-material dispenser 160.
Specifically,
hydraulic fluid 155 flows through end-cap 171 into interior 303 of cartridge
tube 302.
This addition of hydraulic fluid 155 causes plunger 175 to advance within
cartridge
tube 302 in forward plunger direction 181 and away from end-cap 171. As a
result,
flowable material 308 is displaced by plunger 175 out of cartridge tube 302.
The
precision of rotary actuator 120 results in flowable material 308 being
dispensed in a
precisely controlled manner.
Some examples of hydraulic fluid 155 include mineral oils, glycols (e.g.,
propylene glycol), esters, organophosphate esters, polyalphaolefins, and
silicone oils.
Hydraulic fluid 155 is non-compressible. As a result, the volume of hydraulic
fluid 155
displaced from reservoir 140 is the same as the volume of hydraulic fluid 155
received in flowable-material dispenser 160.
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The negative pressure of hydraulic fluid 155 is generated in reservoir 140 by
advancing piston 145 inside reservoir 140 away from the hydraulic fluid outlet
(e.g., a
coupling to conduit 150). The negative pressure of hydraulic fluid 155 is
determined
by the contact area between piston 145 and hydraulic fluid 155 and by the
sealing
.. and supporting force needed between piston 145 and end-cap 171.
Over-center mechanism 179 is attached to end-cap 171 and configured to
move end-cap 171 with piston 145, supported on end-cap 171, between two
positions. In one position, end-cap 171 and piston 145 are spaced away from
cartridge housing 173 or, more specifically, from first end 176 of cartridge
housing
173. This position allows inserting cartridge tube 302 into cartridge housing
173. In
another position, plunger 175 is inserted into interior 303 and hermetically
sealed
against interior 303. In this portion, end-cap 171 is also sealed against
interior 303.
Furthermore, plunger 175 is now movable within interior 303.
Rotary actuator 120 is turned in one of rotational direction 121 and second
rotational direction 122, which causes the transfer of hydraulic fluid 155
between
reservoir 140 and flowable-material dispenser 160. Some examples of rotary
actuator 120 include, but are not limited to, stepper motors, servo motors,
and the
like. These examples provide very precise control of the rotation speed and
the
degree of rotation, which in turn enables flowable material 308 to be
dispensed in
precise quantities.
Referring generally to FIGS. 7A-7B and particularly to, e.g., FIG. 4E,
according
to method 700, (block 722) inserting cartridge tube 302 into cartridge housing
173
comprises hermetically sealing cartridge tube 302 against second end-cap 172
of
flowable-material dispenser 160, attached to cartridge housing 173 opposite of
end-
cap 171. The preceding subject matter of this paragraph characterizes example
27 of
the present disclosure, wherein example 27 also includes the subject matter
according to example 26, above.
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When second end-cap 172 is sealed against cartridge tube 302, flowable
material 308 is directed from cartridge tube 302 through second end-cap 172
and
toward the dispensing tip of flowable-material dispenser 160. This seal
ensures that
flowable material 308 does not flow into space between cartridge tube 302 and
cartridge housing 173, thereby preventing contamination of cartridge housing
173.
The seal is established when cartridge tube 302 is inserted into cartridge
housing 173
and is maintained until cartridge tube 302 is removed from cartridge housing
173.
In some examples, as shown in FIG. 4E, second end-cap 172 comprises
gasket 163 for sealing against cartridge tube 302. Gasket 163 is formed of an
elastomeric material (e.g., rubber). As shown in FIG. 4E, a portion of second
end-cap
172 overlaps with cartridge tube 302 for additional sealing and/or maintaining
orientation of cartridge tube 302. For example, this portion of second end-cap
172
protrudes into cartridge tube 302.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 4A,
4B,
4C, 5A, 5B, according to method 700, (block 730) locking over-center mechanism
179
relative to cartridge housing 173 is performed while plunger 175 is coupled to
end-cap
171 and comprises inserting plunger 175 into interior 303 of cartridge tube
302. The
preceding subject matter of this paragraph characterizes example 28 of the
present
disclosure, wherein example 28 also includes the subject matter according to
example 26 or 27, above.
Over-center mechanism 179 is used to move end-cap 171 and plunger 175
relative to cartridge housing 173. In one position, plunger 175 and end-cap
171 are
positioned away from cartridge housing 173 or, more specifically, away from
first end
176 of cartridge housing 173. In another position, end-cap 171 is positioned
at first
end 176 of cartridge housing 173 and plunger 175 is inserted into cartridge
tube 302.
At this position, over-center mechanism 179 is locked.
36
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End-cap 171 is pivotable by over-center mechanism 179 relative to cartridge
housing 173 as shown, for example, in FIGs. 5A and 5B. In some examples, over-
center mechanism 179 comprises multiple arms pivotably coupled to each other.
The
number and the length of these arms establish the trajectory of end-cap 171
when
end-cap 171 is moved by over-center mechanism 179. In one or more examples,
the
movement of end-cap 171 relative to cartridge housing 173 is substantially
along the
center axis of cartridge housing 173 when end-cap 171 approaches first end 176
of
cartridge housing 173. As described above, end-cap 171 supports plunger 175,
and
plunger 175 is inserted into cartridge tube 302, when end-cap 171 approaches
first
end 176 of cartridge housing 173.
Referring e.g., to FIGS. 7A and 7B, method 700 further comprises (block 750)
monitoring pressure inside reservoir 140. The preceding subject matter of this
paragraph characterizes example 29 of the present disclosure, wherein example
29
also includes the subject matter according to any one of examples 26 to 28,
above.
The pressure inside reservoir 140 is monitored to control the dispensing rate
of
flowable material 308. Furthermore, the pressure inside reservoir 140 is
monitored to
ensure support to plunger 175 by end-cap 171, e.g., when plunger 175 is
extracted
from cartridge tube 302 and moved away from of cartridge housing 173. When
this
pressure, inside reservoir 140, exceeds atmospheric pressure, which is
referred to as
a positive pressure, plunger 175 is forced from first end 176 to second end
177 of
cartridge housing 173. At some point, the positive pressure overcomes the
frictional
resistance of plunger 175, relative to cartridge tube 302, and also the flow
resistance
of flowable material 308, and plunger 175 starts moving from first end 176 to
second
end 177. The speed of this movement depends on the level of this positive
pressure
(relative to the frictional forces and flow resistance). As plunger 175 moves
from first
end 176 to second end 177, plunger 175 displaces flowable material 308 from
cartridge tube 302. As such, the positive pressure controls the plunger speed,
which,
in turn, determines the dispensing rate of flowable material 308.
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When this pressure is a negative pressure (i.e., is below atmospheric
pressure), plunger 175 is forced from second end 177 to first end 176 of
cartridge
housing 173 and against end-cap 171. When end-cap 171 is moved away from
cartridge housing 173, end-cap 171 pulls plunger 175 out of cartridge tube 302
and
supports plunger 175 until plunger 175 is reinserted into a new cartridge
tube.
In one or more examples, the pressure inside reservoir 140 is monitored using
a gauge attached to reservoir 140 or to conduit 150. It should be noted that
the
pressure inside reservoir 140 is the same as in any other volume of apparatus
100
containing hydraulic fluid 155.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 3A
and
3B, according to method 700, (block 740) turning rotary actuator 120 in
rotational
direction 121 is terminated once the pressure inside reservoir 140 reaches a
predetermined level. The preceding subject matter of this paragraph
characterizes
example 30 of the present disclosure, wherein example 30 also includes the
subject
.. matter according to example 29, above.
The pressure inside reservoir 140 is monitored to control the dispensing rate
of
flowable material 308.
Specifically, the positive pressure of hydraulic fluid 155
applies a force to plunger 175 from first end 176 to second end 177 of
cartridge
housing 173, thereby displacing flowable material 308 from cartridge housing
173.
The plunger 175 stops once plunger 175 reaches second end 177. At this point,
supplying an additional portion of hydraulic fluid 155 from reservoir 140 to
cartridge
housing 173 will increase the pressure of hydraulic fluid 155. To ensure
safety and to
prevent damage of various components of apparatus 100 from excessive pressure
of
hydraulic fluid 155, turning rotary actuator 120 in rotational direction 121
is terminated
once the pressure inside reservoir 140 reaches the predetermined level. In one
or
more examples, even before plunger 175 reaches second end 177, the pressure
inside reservoir 140 is controlled for the same reasons and also to prevent
excessive
dispensing rates of flowable material 308.
38
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In one or more examples, the pressure inside reservoir 140 is monitored using
a gauge, attached to reservoir 140 or conduit 150. In these examples, the
gauge is
coupled to the switch, which controls rotary actuator 120, e.g., either
directly or
through a central controller.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 3A
and
3B, method 700 further comprises (block 760) turning rotary actuator 120 in
second
rotational direction 122, opposite of rotational direction 121, so that linear
actuator
130 retracts piston 145 within reservoir 140 and at least a portion of
hydraulic fluid
155 is transferred from flowable-material dispenser 160 to reservoir 140,
causing
plunger 175 to retract within cartridge tube 302 in reverse plunger direction
182,
opposite of forward plunger direction 181. The preceding subject matter of
this
paragraph characterizes example 31 of the present disclosure, wherein example
31
also includes the subject matter according to any one of examples 26 to 30,
above.
Turning rotary actuator 120 in second rotational direction 122 results in
piston
145 moving away from the hydraulic fluid exit in reservoir 140. As a result,
hydraulic
fluid 155 is being transferred from flowable-material dispenser 160 to
reservoir 140
during this operation. This transfer of hydraulic fluid 155 creates a negative
pressure
in hydraulic fluid 155. This negative pressure causes plunger 175 to retract
within
cartridge tube 302 in reverse plunger direction 182, opposite of forward
plunger
direction 181. Specifically, plunger 175 moves from second end 177 to first
end 176
of cartridge housing 173.
In general, rotary actuator 120 is configured to turn in rotational direction
121
or second rotational direction 122 at different times. Some examples of rotary
actuator 120 having this functionality, include, but are not limited to,
stepper motors,
servo motors, and the like. Furthermore, these examples ensure precise control
of
the rotation speed and the degree of rotation, which in turn translates into
precise
dispensing of flowable material 308.
39
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Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 3A
and
3B, according to method 700, (block 760) turning rotary actuator 120 in second
rotational direction 122 comprises (block 762) monitoring pressure inside
reservoir
140. The preceding subject matter of this paragraph characterizes example 32
of the
present disclosure, wherein example 32 also includes the subject matter
according to
example 31, above.
The pressure inside reservoir 140 is monitored to determine when plunger 175
reaches end-cap 171. Specifically, as rotary actuator 120 is turned in second
rotational direction 122 and hydraulic fluid 155 is transferred from interior
303 of
cartridge tube 302 to reservoir 140, plunger 175 moves toward end-cap 171.
Once
plunger 175 reaches end-cap 171, plunger 175 stops. At this point,
transferring an
additional portion of hydraulic fluid 155 from interior 303 of cartridge tube
302 to
reservoir 140 simply decreases the pressure of hydraulic fluid 155. To ensure
safety
and to prevent damage of various components of apparatus 100 from excessive
negative pressure of hydraulic fluid 155, the pressure of hydraulic fluid 155
inside
reservoir 140 is monitored.
In one or more examples, the pressure inside reservoir 140 is monitored using
a gauge attached to reservoir 140 or to conduit 150.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 3A
and
3B, according to method 700, (block 760) turning rotary actuator 120 in second
rotational direction 122 is terminated once pressure inside reservoir 140
reaches a
predetermined level. The preceding subject matter of this paragraph
characterizes
example 33 of the present disclosure, wherein example 33 also includes the
subject
matter according to example 32, above.
The pressure inside reservoir 140 is monitored to determine when plunger 175
reaches end-cap 171. Specifically, as rotary actuator 120 is turned in second
rotational direction 122 and hydraulic fluid 155 is transferred from interior
303 of
CA 3052166 2019-08-14
cartridge tube 302 to reservoir 140, plunger 175 moves toward end-cap 171.
Once
plunger 175 reaches end-cap 171, plunger 175 stops. At this point,
transferring an
additional portion of hydraulic fluid 155 from interior 303 of cartridge tube
302 to
reservoir 140 simply decreases the pressure of hydraulic fluid 155. To ensure
safety
and to prevent damage of various components of apparatus 100 from excessive
negative pressure of hydraulic fluid 155, the pressure of hydraulic fluid 155
inside
reservoir 140 is monitored. Once the pressure reaches the predetermined level,
turning rotary actuator 120 in second rotational direction 122 is terminated.
In one or more examples, the pressure inside reservoir 140 is monitored using
a gauge attached to reservoir 140 or to conduit 150. In these examples, the
gauge is
coupled to the switch, which controls rotary actuator 120, e.g., either
directly or
through a central controller. In one or more examples, the predetermined level
of the
pressure is determined to ensure support of plunger 175 on end-cap 171.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIG. 3A,
3B,
4C, according to method 700, (block 760) turning rotary actuator 120 in second
rotational direction 122 comprises (block 764) hermetically sealing plunger
175
against end-cap 171. The preceding subject matter of this paragraph
characterizes
example 34 of the present disclosure, wherein example 34 also includes the
subject
matter according to any one of examples 31 to 33, above.
Plunger 175 stops once plunger 175 reaches end-cap 171. At this point,
transferring an additional amount of hydraulic fluid 155 from interior 303 of
cartridge
tube 302 to reservoir 140 decreases the pressure of hydraulic fluid 155,
thereby
creating negative pressure. This negative pressure forces plunger 175 against
end-
cap 171 and forms a hermetic seal between plunger 175 and end-cap 171. As
such,
this hermetic seal ensures support of plunger 175 in end-cap 171. Furthermore,
the
hermetic seal ensures that the negative pressure is maintained and that air is
not
introduced into hydraulic fluid 155.
41
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Referring to FIG. 4C, plunger 175 is shown directly contacting end-cap 171.
The hermetic seal is provided by direct contact between plunger 175 and end-
cap
171. Furthermore, in one or more examples, second gasket 422, disposed between
plunger 175 and end-cap 171, is used to form the hermetic seal.
Referring generally to FIGS. 7A and7B, and particularly to, e.g., FIG. 4E,
according to method 700, (block 760) turning rotary actuator 120 in second
rotational
direction 122 comprises (block 766) admitting atmosphere into cartridge tube
302
through vent 162, located in cartridge housing 173. The preceding subject
matter of
this paragraph characterizes example 35 of the present disclosure, wherein
example
35 also includes the subject matter according to any one of examples 31 to 34,
above.
As described above, turning rotary actuator 120 in a second rotational
direction
122 causes movement of plunger 175 away from second end 177 of cartridge
housing 173. Vent 162 admits the atmosphere into cartridge tube 302 during
this
operation, effectively backfilling cartridge tube 302, e.g., with atmosphere.
This
backfill prevents flowable material 308 from being pulled back into cartridge
tube 302.
Furthermore, the backfill prevents the negative pressure from building up
inside
cartridge tube 302 (e.g., between plunger 175 away from second end 177 of
cartridge
housing 173).
In one or more examples, vent 162 comprises a valve, one end of which is in
fluid communication with interior 303 of cartridge tube 302 (when cartridge
tube 302 is
positioned inside cartridge housing 173). The other end of this valve is open
to the
atmosphere. In one or more examples, the operation of vent 162 is synchronized
with operation of other components of apparatus 100, such as rotary actuator
120.
Specifically, vent 162 allows the atmosphere to enter cartridge tube 302 when
rotary
actuator 120 is turning in second rotational direction 122, resulting in the
transfer of
hydraulic fluid 155 from flowable-material dispenser 160 to reservoir 140.
42
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Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIG. 4C,
according to method 700, plunger 175 is retracted within cartridge tube 302
until
annular boss 427 of end-cap 171 protrudes into annular recess 429 of plunger
175.
The preceding subject matter of this paragraph characterizes example 36 of the
present disclosure, wherein example 36 also includes the subject matter
according to
any one of examples 31 to 35, above.
When annular boss 427 of end-cap 171 protrudes into annular recess 429 of
plunger 175, a geometric coupling is formed between end-cap 171 and plunger
175.
This geometric coupling is used in addition to or instead of the vacuum
coupling
between end-cap 171 and plunger 175 caused by the negative pressure of
hydraulic
fluid 155.
In one or more examples, annular boss 427 of end-cap 171 and annular recess
429 of plunger 175 have interference fit. In these examples, plunger 175 is
formed
from a flexible material (e.g., elastomer).
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIG. 5A,
method 700 further comprises (block 770) unlocking over-center mechanism 179
relative to cartridge housing 173 to move plunger 175 and end-cap 171 away
from
cartridge tube 302 and cartridge housing 173. The preceding subject matter of
this
paragraph characterizes example 37 of the present disclosure, wherein example
37
.. also includes the subject matter according to any one of examples 26 to 36,
above.
Plunger 175 and end-cap 171 are moved away from cartridge tube 302 and
cartridge housing 173 to provide access to cartridge tube 302. This position
of
plunger 175 and end-cap 171 allows removal of cartridge tube 302 from
cartridge
housing 173 (e.g., to replace cartridge tube 302 with new cartridge tube when
flowable material 308 is dispensed from cartridge tube 302).
End-cap 171 is pivotable by over-center mechanism 179 relative to cartridge
housing 173 as shown, for example, in FIGs. 5A and 5B. In some examples, over-
43
CA 3052166 2019-08-14
center mechanism 179 comprises multiple arms pivotably coupled to each other.
The
number and the length of these arms establish the trajectory of end-cap 171
when
end-cap 171 is moved by over-center mechanism 179.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIG. 5A,
according to method 700, (block 770) unlocking over-center mechanism 179
relative
to cartridge housing 173 comprises (block 772) coupling plunger 175 to end-cap
171.
The preceding subject matter of this paragraph characterizes example 38 of the
present disclosure, wherein example 38 also includes the subject matter
according to
example 37, above.
This coupling supports plunger 175 relative to end-cap 171 when plunger 175
is extracted from cartridge tube 302. Furthermore, this coupling supports
plunger 175
relative to end-cap 171 when plunger 175 and end-cap 171 are moved away from
cartridge tube 302.
Plunger 175 is coupled to end-cap 171, for example, using the negative
pressure of hydraulic fluid 155. The negative pressure is created when plunger
175 is
positioned against end-cap 171 and rotary actuator 120 continues to turn in
second
rotational direction 122.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIG. 5A,
according to method 700, (block 772) coupling plunger 175 to end-cap 171
comprises
(block 774) maintaining negative pressure of hydraulic fluid 155 at least in
reservoir
140. The preceding subject matter of this paragraph characterizes example 39
of the
present disclosure, wherein example 39 also includes the subject matter
according to
example 38, above.
Maintaining the negative pressure of hydraulic fluid 155 at least in reservoir
140 also maintains the negative pressure of hydraulic fluid 155 in other
portions of
apparatus 100 due to hydraulic coupling and flow of hydraulic fluid 155
between
44
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reservoir 140 and other portions. Specifically, the negative pressure of
hydraulic fluid
155 forces plunger 175 against end-cap 171.
Referring generally to, e.g., FIGS. 7B, method 700 further comprises (block
780) removing cartridge tube 302 from cartridge housing 173. The preceding
subject
.. matter of this paragraph characterizes example 40 of the present
disclosure, wherein
example 40 also includes the subject matter according to any one of examples
26 to
39, above.
Cartridge tube 302 is removed from cartridge housing 173 when flowable
material 308 is dispensed from cartridge tube 302. For example, a new
cartridge tube
.. is later placed inside cartridge housing 173 to replace cartridge tube 302.
To remove
cartridge tube 302, end-cap 171 is positioned away from cartridge housing 173
providing access to cartridge housing 173. In one or more examples, end-cap
171
supports plunger 175
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 6A
and
6B, method 700 further comprises (block 756) opening dispenser valve 600 of
flowable-material dispenser 160, fluidically coupled to interior 303 of
cartridge tube
302, to enable flowable material 308 to flow from apparatus 100. The preceding
subject matter of this paragraph characterizes example 41 of the present
disclosure,
wherein example 41 also includes the subject matter according to any one of
examples 26 to 40, above.
Dispenser valve 600 controls the flow of flowable material 308 from apparatus
100. In one or more examples, when flowable material 308 is not dispensed,
dispenser valve 600 is kept closed. As such, flowable material 308 is isolated
from
the environment (e.g., to prevent curing of flowable material 308 remaining in
apparatus 100).
CA 3052166 2019-08-14
In one or more examples, dispenser valve 600 is coupled to second double-
acting pneumatic cylinder 520, which opens and closes dispenser valve 600, as
shown in FIGS. 6A and 6B.
Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 6A
and
6B, according to method 700, (block 756) opening dispenser valve 600 is
synchronized with turning rotary actuator 120 in rotational direction 121. The
preceding subject matter of this paragraph characterizes example 42 of the
present
disclosure, wherein example 42 also includes the subject matter according to
example 41, above.
Both dispenser valve 600 and rotary actuator 120 control the flow of flowable
material 308 from apparatus 100. Specifically, when rotary actuator 120 turns
in
rotational direction 121, hydraulic fluid 155 is transferred from reservoir
140 to interior
303 of cartridge tube 302, thereby causing movement of plunger 175 and
dispensing
of flowable material 308. Dispenser valve 600 controls the flow path of
flowable
material 308 from cartridge tube 302. Therefore, flowable material 308 is
dispensed
only when dispenser valve 600 is open and rotary actuator 120 is turning in a
rotational direction. Flowable material 308 is not dispensed when either
dispenser
valve 600 is closed or rotary actuator 120 does not turn in the rotational
direction.
In one or more examples, dispenser valve 600 is immediately open when
rotary actuator 120 begins turning in the rotational direction. This
synchronization
prevents building up an excessive hydraulic pressure in apparatus 100, which
is
otherwise possible when dispenser valve 600 remains closed while rotary
actuator
120 continues turning in the rotational direction. In the same or other
examples,
dispenser valve 600 is closed as soon as rotary actuator 120 stops turning in
the
rotational direction. This feature prevents exposure of a portion of flowable
material
308, remaining in apparatus 100, to the environment. In one or more examples,
dispenser valve 600 remains closed even when rotary actuator 120 starts
turning in
second rotational direction 122, opposite of rotational direction 121.
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Referring generally to FIGS. 7A and 7B, and particularly to, e.g., FIGS. 3B
and
3C-3F, according to method 700, piston 145 is coupled to rotary actuator 120
by
screw 135 and ball nut 134. Piston 145 does not rotate relative to reservoir
140 as
piston 145 advances or retracts within reservoir 140. The preceding subject
matter
of this paragraph characterizes example 43 of the present disclosure, wherein
example 43 also includes the subject matter according to any one of examples
26 to
42, above.
Screw 135 is non-rotatably coupled to piston 145 and is linearly advanced
along central axis 131 by rotating ball nut 134 relative to screw 135 as
schematically
shown, for example, in FIG. 3B. As such, the rotation of ball nut 134 relative
to screw
135 determines the linear motion of screw 135 and piston 145 and also
determines
the transfer of hydraulic fluid 155 to and from reservoir 140. When piston 145
does
not rotate relative to reservoir 140, screw 135 also does not rotate relative
to reservoir
140 and other stationary components of apparatus 100. As such, the rotation of
ball
nut 134 relative to screw 135 is precisely controllable by rotary actuator
120, which is
coupled to ball nut 134 by gear train 125. In other words, the rotation of
ball nut 134
relative to screw 135 is only controlled by the rotation of rotary actuator
120, since
screw 135 and piston 145 do not rotate.
FIGS. 3C-3F illustrate various examples of features and mechanisms used to
ensure that piston 145 does not rotate relative to reservoir 140 yet is able
to advance
and/or retract within reservoir 140 along central axis 131. Specifically, FIG.
3C
illustrates anti-rotation mechanism 139, which comprises slot 192 and
protrusion 191
protruding into slot 192. Slot 192 is formed in screw 135, while protrusion
191 is
attached to housing 138 of linear actuator 130. However, other arrangements
are
also within the scope of the present disclosure, e.g., a slot in housing 138
and a
protrusion in screw 135, a slot in piston 145 and a protrusion in reservoir
140, a slot in
reservoir 140 and a protrusion in piston 145, and the like. Both slot 192 and
protrusion 191 extend along central axis 131 of screw 135, which allows piston
145 to
advance and/or retract within reservoir 140 along central axis 131.
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FIG. 3C illustrates another example of anti-rotation mechanism 139, which
comprises first surface 193, and second surface 194 slidably contacting first
surface
193 at least two points of first surface 193 that lie on opposite sides of
orthogonal
projection 132 of central axis 131 onto first surface 193. In this example,
first surface
193 is on screw 135, while second surface 194 is on protrusion 191 attached to
housing 138. However, other arrangements are also within the scope of the
present
disclosure.
FIGS. 3E and 3F illustrate two examples of cross-sections of piston 145 and
reservoir 140 in a plane perpendicular to central axis 131. These examples
show
piston 145 and reservoir 140 having complementary non-circular cross-sections.
These non-circular cross-sections provide a seal between piston 145 and
reservoir
140 and allow piston 145 to advance and/or retract within reservoir 140 along
central
axis 131. FIG. 3E illustrates a specific example where these complementary non-
circular cross-sections are oval. FIG. 3E illustrates another example where
these
complementary non-circular cross-sections are rectangular.
Examples of the present disclosure may be described in the context of method
1100 for aircraft manufacturing and service as shown in FIG. 8A and aircraft
1102 as
shown in FIG. 8B. During pre-production, method 1100 may include specification
and
design (block 1104) of aircraft 1102 and material procurement (block 1106).
During
production, component and subassembly manufacturing (block 1108) and system
integration (block 1110) of aircraft 1102 may take place. Thereafter, aircraft
1102
may go through certification and delivery (block 1112) to be placed in service
(block
1114). While in service, aircraft 1102 may be scheduled for routine
maintenance and
service (block 1116). Routine maintenance and service may include
modification,
reconfiguration, refurbishment, etc. of one or more systems of aircraft 1102.
Each of the processes of method 1100 may be performed or carried out by a
system integrator, a third party, and/or an operator (e.g., a customer). For
the
purposes of this desbription, a system integrator may include, without
limitation, any
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number of aircraft manufacturers and major-system subcontractors; a third
party may
include, without limitation, any number of vendors, subcontractors, and
suppliers; and
an operator may be an airline, leasing company, military entity, service
organization,
and so on.
As shown in FIG.8B, aircraft 1102 produced by method 1100 may include
airframe 1118 with a plurality of high-level systems 1120 and interior 1122.
Examples
of high-level systems 1120 include one or more of propulsion system 1124,
electrical
system 1126, hydraulic system 1128, and environmental system 1130. Any number
of other systems may be included. Although an aerospace example is shown, the
principles disclosed herein may be applied to other industries, such as the
automotive
industry. Accordingly, in addition to aircraft 1102, the principles disclosed
herein may
apply to other vehicles, e.g., land vehicles, marine vehicles, space vehicles,
etc.
Apparatus(es) and method(s) shown or described herein may be employed
during any one or more of the stages of method 1100. For example, components
or
subassemblies corresponding to component and subassembly manufacturing (block
1108) may be fabricated or manufactured in a manner similar to components or
subassemblies produced while aircraft 1102 is in service (block 1114). Also,
one or
more examples of the apparatus(es), method(s), or combination thereof may be
utilized during production stages (shown as block 1108 and block 1110), for
example,
by substantially expediting assembly of or reducing the cost of aircraft 1102.
Similarly, one or more examples of the apparatus or method realizations, or a
combination thereof, may be utilized, for example and without limitation,
while aircraft
1102 is in service (block 1114) and/or during maintenance and service (block
1116).
Different examples of the apparatus(es) and method(s) disclosed herein
include a variety of components, features, and functionalities. It should
be
understood that the various examples of the apparatus(es) and method(s)
disclosed
herein may include any of the components, features, and functionalities of any
of the
other examples of the apparatus(es) and method(s) disclosed herein in any
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combination, and all of such possibilities are intended to be within the scope
of the
present disclosure.
Many modifications of examples set forth herein will come to mind to one
skilled in the art to which the present disclosure pertains having the benefit
of the
teachings presented in the foregoing descriptions and the associated drawings.
Therefore, it is to be understood that the present disclosure is not to be
limited
to the specific examples illustrated and that modifications and other examples
are
intended to be included within the scope of the appended claims. Moreover,
although
the foregoing description and the associated drawings describe examples of the
present disclosure in the context of certain illustrative combinations of
elements
and/or functions, it should be appreciated that different combinations of
elements
and/or functions may be provided by alternative implementations without
departing
from the scope of the appended claims.
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